isomorphic-git is a pure JavaScript implementation of Git for Node.js and browsers.
CVE-2026-63395
isomorphic-git is a pure JavaScript implementation of Git for Node.js and browsers. Prior to 1.38.6, isomorphic-git's git.checkout writes new child paths through symlinked leading directory components without checking them. A malicious repository can first place a directory symlink and later replace the tree state with a child file beneath that path; the usual trigger is a clone followed by a later pull, while a single clone can trigger the issue when a symlink already exists or the consuming application accesses the tree. With Node fs on Linux or macOS, the operating system can resolve the write outside the working tree, permitting arbitrary host file writes and possible code execution. Node fs on Windows usually blocks the symlink plant without additional privilege, and browser or in-memory providers limit impact to their virtual filesystem and are affected only when they implement symlink creation and following. This issue is fixed in version 1.38.6.
Assessment
- CVSS
- 8.8 (v3.1)
- Severity
- High
- Known exploited
- Not listed in CISA KEV
- Exploit availability
- Nothing found in Exploit-DB, Metasploit, Nuclei or public PoC repositories
- Published
- 3 November 2026
- Last updated
- 3 November 2026
- Affected
- isomorphic-git · isomorphic-git
- Assigner
- GitHub_M
CVSS vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
At the source
References
- https://github.com/isomorphic-git/isomorphic-git/security/advisories/GHSA-9qw7-j9xw-fv9c
- https://github.com/isomorphic-git/isomorphic-git/pull/2370
- https://github.com/isomorphic-git/isomorphic-git/commit/823843d1cd19182df79bc907c767f5bcecb39a0b
- https://github.com/isomorphic-git/isomorphic-git/releases/tag/v1.38.6
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